The present invention relates to a heating element of a cigar lighter, and more particularly to a thermally controlled switching element in a cigar or cigarette lighter.
Various lighters are known for automotive applications, including lighters shown in the following U.S. Pat. Nos. 4,168,422; 4,204,109; 4,207,455; 4,177,374; 5,998,763; and 4,230,931. U.S. Pat. No. 6,740,850 discloses an electric cigar lighter assembly that has a lighter heating assembly 100 that plugs into a socket assembly 300. The lighter assembly 100 includes a heating element 122 and a switch. The switch is comprised of contacts 142 and 154. FIG. 1 shows the lighter assembly 100 inserted into the socket 300 but un-energized because the contacts 142, 154 are not in electrical contact. When the knob 102 is pushed in, thus forcing the lighter 100 into the socket assembly 300 further, the contacts 142, 154 engage in the heater 122 is electrically energized. After a period of time, a bimetallic disk 146 heats up and moves from the position shown in FIG. 1B to the position shown in FIG. 1 by the bold lines, thereby forcing the lighter 100 outwardly and disengaging the contacts 142 and 154, thus de-energizing the heater 122. A problem with this construction is that the single bimetallic disk 146 is used to cause the lighter to pop-up when the heating element reaches a desired temperature. The problem with such a single bimetallic disk is that it is difficult to provide controlled upper and lower limits of a temperature window for operation of the bimetallic disk.
U.S. Pat. No. 2,137,195 teaches a cigar lighter that has a heating element carried within and connected to a metal cup and also to a central stud. The cup is one of two contacts that are brought together to place the heating element in the energizing circuit. The other contact, however, is not a thermostatic element, but another part carried by the thermostatic element and, in particular, a permanently dished metal plate. This plate is centrally riveted to the center of the thermostatic element which is normally uniplanar. The heat responsive deformation of the thermostatic element pushes against the metal plate to force the lighter assembly out of the socket.